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    SubjectRe: [PATCH] ramfs: ignore tmpfs options when we emulate it
    On Sat, Jun 13, 2009 at 10:15, Hugh Dickins wrote:
    > On Sat, 13 Jun 2009, Mike Frysinger wrote:
    >> On systems where CONFIG_SHMEM is disabled, mounting tmpfs filesystems can
    >> fail when tmpfs options are used.  This is because tmpfs creates a small
    >> wrapper around ramfs which rejects unknown options, and ramfs itself only
    >> supports a tiny subset of what tmpfs supports.  This makes it pretty hard
    >> to use the same userspace systems across different configuration systems.
    >> As such, ramfs should ignore the tmpfs options when tmpfs is merely a
    >> wrapper around ramfs.
    > Yes, indeed, thanks a lot for reporting this.
    > But I'm uneasy with making ramfs behaviour differ with CONFIG_SHMEM
    > (perhaps that's silly: certainly tmpfs behaviour differs with it),
    > and uneasy with coding a list of options we need to remember to keep
    > in synch with mm/shmem.c.  It's easier to justify ignoring all options,
    > than rejecting some while ignoring others yet not respecting them.


    >> This used to work before commit c3b1b1cbf0 as previously, ramfs would
    >> ignore all options.  But now, we get:
    >> ramfs: bad mount option: size=10M
    >> mount: mounting mdev on /dev failed: Invalid argument
    > I rather think the correct response to bugzilla #12843 should have
    > been to say, either use chmod 1777 yourself, or use CONFIG_SHMEM=y.
    > I fear we'll now get a line of requests for support of uid, gid, ...
    > in ramfs; whereas ramfs is about blind simplicity, not feature bloat.
    > However, that mode= feature is now in, so I guess we ride with it.

    i thought the bug report a bit odd in more than just this regard.
    glad to see i'm not the only one ;).

    >> another option might be to restore the previous behavior where ramfs simply
    >> ignored all unknown mount options ...
    > Yes, that would be my preference, return to the blind simplicity, with
    > that one exception for mode=.  Alternative patch suggested at the bottom,
    > let's see if Cc's added feel strongly about it one way or another.

    i'm OK with either approach, thanks !
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